Volkswagen Golf/Jetta 2 manual

Fuel injectors - removal, testing and refitting
Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines / Fuel injectors - removal, testing and refitting

1 An injector may give trouble for one of the following reasons:
a) The spray may be irregular in shape b) The nozzle may not close when the engine is shut down, causing flooding when restarting
c) The nozzle filter may be choked, giving less that the required ration of fuel d) The seal may be damaged, allowing an air leak
2 To remove an injector for inspection, simply pull it free (see illustration).

13.2 Air shrouded injector assembly (later models)
13.2 Air shrouded injector assembly (later models)

1 Injector
2 Rubber rings
3 Injector insert
4 Washer

3 Inspect the rubber seal. If it shows signs of cracking, distortion or perishing, then it must be renewed. If found to be defective, check the other injector seals as they are likely to be in similar condition.

4 Specialised tools are required for an accurate test of injector performance.

However, a basic check can be made as follows.

5 Hold the injector in a suitable measuring glass and plug up the injector location hole.

Start the engine and let it idle on three cylinders and look at the shape of the spray. It should be of a symmetrical cone shape. If it is not, then the injector must be changed because the vibrator pin is damaged or the spring is broken. Shut off the engine and wait for 15 seconds. There must be no leak or dribble from the nozzle. If there is, the injector must be renewed, as dribble will cause flooding and difficult starting.

6 An injector cannot be dismantled for cleaning. If an injector is renewed, the line union must be tightened to the specified torque.

7 When inserting an injector, lubricate the seal with fuel before fitting.

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